SAR Calculations in Human Head Model Extracted from Thermal Infrared Images

In electromagnetic dosimetry, anatomical human models are commonly obtained by segmentation of magnetic resonance imaging (MRI) or computed tomography (CT) scans. In this paper, a human head model extracted from thermal IR images is examined in terms of its applicability to specific absorption rate (SAR) calculations. Since thermal scans are two-dimensional (2-D) representation of surface temperature, this allows researchers to overcome the extensive computational demand associated with three-dimensional (3-D) simulation. The numerical calculations are performed using the finite difference time domain (FDTD) method with mesh sizes of 2 mm at 900 MHz plane wave irradiation. The power density of the incident plane wave is assumed to be 10 W/m2. Computations were compared with a realistic anatomical head model. The results show that although there were marked differences in the local SAR distribution in the various tissues in the two models, the 1g peak SAR values are approximately similar in the two models.